Recent investigations show that the primary somatosensory cortex undergoes topographic remodeling after peripheral nerve injury and after subsequent nerve regeneration. The overall objective of the proposed research is to understand the cortical consequences of nerve injury and nerve regeneration and to identify patterns of cortical recovery that are necessary to restore good sensory function after peripheral injury. In working toward this objective, in the proposed research for the upcoming year the primary somatosensory cortex of monkeys will be studied with neurophysiological recording techniques after peripheral nerve injury. The specific aims are to: (1) complete studies begun during year 01 on the cortical consequences of different types of peripheral injury, and (2) perform studies on the limitations in the capacity of cortex to recover cutaneous responsiveness after nerve transection injuries involving different degrees of denervation. Depending on the outcome of these experiments, it may also be possible to begin the study of the long-term cortical effects of nerve repair.